Sound amplifier



Feb. 16 ,.1926. 1,573,634 c. J. DODGE SOUND AMPLIFIER Filed August 18, 1922 J l/l/ll/l/ll/l/l/ [Ill /7]7 Patented Feb. 16, 1.925.

CHARLES J. DODGE, OF BROOKLYN, NEW YORK.

SOUND AMPLIFIER.

Application filed August 18, 1922.

To (ZZZ whom it may concern:

Be it known that I, CHARLES J. Donor, a citizen of the United States, and a resident of the borough of Brooklyn, city and State of New York, have invented certain new and useful Improvements in Sound Amplitiers, of which the following is a specification.

The present invention relates to sound amplifiers or horns. The object of the invention is to provide a sound amplifier which is adapted to serve a dual purpose: that is, the device may serve either as a sound amplifier for the sound waves received from a phonograph reproducer opcrated from a phonograph record and also as an amplifier for the sound waves created in a telephone receiver. \Vith the present device it is a simple matter to combine the parts of a phonograph and the receiver of a wireless telephone whereby one and the same amplifier may serve to amplify the sounds reproduced from the phonograph and also serve as a loud speaker for a wire less telephone set. While in most cases the telephone and phonograph will be used se arately the present device is such that the equipment for both uses may be per1na nently attached to the amplifier so that either the phonograph or telephone may be operated at any time without interchanging or disconnecting any parts of the combined apparatus.

The amplifier has two inlet sections which deliver the sound waves from different sources, i. e., from the reproducer or the receiver, into a common amplifying chamber or horn, so that the greater portion of the amplifier is common to both sources of sound. These inlet sources are so connected and directed in relation to each other and to the common sound cham er that the sound waves from either source will take a direct course from the source of sound through the amplifier without passing into the inlet from the other sound sou co and without being affected in tone by the unused sound inlet. In other words, either sound inlet may be used and the tone will be practically the same as if the other inlet were not present in the structure and therefore I secure the same acoustic result as if two separate amplifiers were used for the two separate sources of sound.

Another object of my invention is to provide a device of the combined type wherein Serial No. 582,692.

the course of travel and the gradual increase in area of the sound waves will be approximately the same from either source of sound. Thus I provide for the same gradual amplification of the sound waves delivered from the reproducor as well as.

those delivered from the telephone receiver and I secure the best results in a combined apparatus.

Another object of my invention is to so construct the amplifier that it may be incorporated in the ordinary form of phonegraph and at the same time serve as a combined apparatus.

In the drawing forming part of this applieation,

Figure 1 is a side elevation of an amplifier embodying my invention in the preferred form,

Figure 2. is a longitudinal sectional view thereof taken on the line 22 of Figure 3,

Figure 3 is a plan view of the amplifier,

Figure l is an end view showing the receiver cup attached to one of the sound inlets, and

Fi ure 5 is a sectional view taken on the line o-5 of Figure at.

The amplifier 1 is here shown mounted in a phonograph cabinet 2 of ordinary construction to conform to the concealed horn type. The tone arm 3 which will, of course, carry some standard form of reproducer on its free end 4, is pivoted at its rear end 5 so that the arm swings horizontally above the motor shelf 6. The other working parts of the phonograph such as the motor, turn table etc. are omitted from the drawing as these my conform to present practice. The horn ment 8 lying between the motor board 6 and the shelf 9.

The tone arm 3 preferably connects with a sleeve 10 mounted in one end of the throat ll. The horn starts with a curved throat 11 the bore 12 of which is in communication with the bore of the tone arm 3. The throat is curved at 13 to bring the axis of the amplifier horizontal in the horn portion 7. The horn 7 is really a continuation of the throat and both the throat and horn have a sound space which increases in cross sectional area in the direction of travel of the sound waves, the horn terminating in the arge delivery end 1st. The sound waves from tho reproducer on the end of the tone arm 3 pass through the tone arm, thence proper "T disposed in the compartthrough the throat 11 and thence through the horn '7, these several members constitu ing the sound amplifier for the phonographic reproductions. The tone arm forms one inlet to the horn for sound waves.

There is a tubular member 15, here shown as lying close to and just to one side. of the plane of the throat 11 and the telephone receiver is adapted to be attached to this member. I have shown the cup 16 fastened to the member 15 and the receiver (not shown) is adapted to be screwed onto his cup so that the sound waves from the diaphragm of the telephone receiver pass into ,he member 15. The member 15 which forms the second inlet member of the amplifier, curves upwardly in almost circular formation at 16 thence backwardly at 17 and it then curves downwardly at 18 and unites with the threat at the point 19. The bore of the inlet member 15 also communicates with the bore of the throat l1 and of the horn, so that sound waves created at the receiver pass successively through the member 15, the throat 11 and the horn 7.

The device may be and preferably 1s, so made that the distance traveled by the sound waves originating at the reprodueer end of the tone arm and passing out the large end of the horn, will be approximately equal to the distance traveled by the sound waves originating at the receiver and passing out the large end of the horn. In this way the same horn may be properly proportioned for sound waves entering from either inlet. The member 15 is preferably disposed below the motor shelf 6 as shown, so that it does not detract from the appearance of the phono graph since it is concealed in the compartment 8.

The angle and direction at which the bore 20 of the inlet member 15 mer es with the bore of the amplifier is very important. It will be noted that the sound waves passing through the inlet member 15 when they arrive at the junction of the amplifier, i. e., in the form shown, the throat,they are traveling in a downward direction so that they tend to continue in the direction of the bore 12 of the throat rather than to turn upwardly toward the tone arm. As a result, the effect of the amplification from the receiver is the same as if a separate amplifier were used for the receiver consisting only of the members 15, 11 and 7. The sound waves from the inlet member 15 do not pass into the tone arm 3 nor are they materially affected by the presence of the tone arm. On the other hand, when sound waves are passing from the rcproducer through the tone arm 3 and inlet member 12 these waves have no tendency to pass into the inlet member 15 owing to the direction of these waves as they enter the threat 1]. Nor are those latter waves materially all ected by the presence of the inlet member 15. Therefore, the device is as cllicient as if two separate amplifiers YOlO made for the separate purposes. The curvature of the throat 11 where the inlet member 15 unites therewith is practically a continuation of the arc of curvature of the inlet member 15 so thatthe sound waves do not undergo a change of direction while passing from the inlet member 15 into the throat 11. The member 12 joins the throat (in the preferred embodiment of my in vention) at a tangent to the curve of the throat. I have found that this arrangement permits the use of separate inlet members joining a common horn and that the sound waves entering through either inlet are not materially affected by the presence of the other inlet.

With the present device it is not necessary to remove the reproducer or make any change in the tone arm when the receiver alone is being used, and vice versa, it is not necessary to remove the receiver or to make any change in the inlet member 15 when the reproducer is being used.

Having described my invention what I claim is:-

,A sound amplifier comprising a horn body, a curved throat communicating therewith, a curved inlet member having its bore communicating with the bore of said throat, said throat at the place of juncture of said inlet member therewith beingcurved to form a continuation of the curvature of said inlet member, and a second inlet men'iner having its bore communicating with the bore of said throat, saic second inlet member being curved and disposed eccentrically within the arc of curvature of said first inlet member.

Signed at the city, county and State of New York, this 5th day of May, 1922.

CHAS. J. DODGE. 

